Biochemical mechanisms determining the molecular nature of genetic restriction of DNA in chromatin will be studied. Isolated chromatin from cells producing specific, definable protein species (nucleated erythrocytes, plasma cell tumors, etc.) will be used as a template for the in vitro synthesis of RNA. Using DNA complementary to isolate m-RNA, the transcriptional activity of specific genes will be determined. Through reconstitution of various chromosomal protein fractions to DNA, the biochemical nature of proteins will be studied which restrict or activate genes responsible for transcription of the specific m-RNAs. The chromosomal nonhistone proteins will be fractionated and characterized. Their specific interactions with DNA will be determined. The role of nonhistone protein phosphorylation and its contribution to gene regulation will be investigated together with the enzymes responsible for phosphorylation of chromosomal nonhistone proteins (phosphoprotein kinases). BIBLIOGRAPHIC REFERENCES: L. Klysejko-Stefanowicz, J. F. Chiu, Y. H. Tsai, and L. S. Hnilica, "Acceptor Proteins in Rat Androgenic Tissue Chromatin", Proc. Natl. Acad. Sci. U.S.A. 73: 1954, 1976. J. A. Thomson, W. P. Brade, J. F. Chiu and L. S. Hnilica, "In vivo and In vitro Phosphorylation of Nuclear Proteins in Rat Liver", Canad. J. Biochem., 54: 86, 1976.